A very irritating thing in the kindle touch, especially for those who don't use the kindle store, is the store button on the search bar. We could remove this in < 5.1.0 but now that doesn't work. Here's how you turn that button into a browser button (detailed enough for a noob to follow):
First download the attachment, extract it and save "store.png" in /mnt/us i.e the usb drive.
Then ssh into the kindle and enter in:

Music player: probably yes. In fact, I suspect it works for pretty much everything that has an associated URL; it seems to be essentially the same mechanism as described here.

Yep! I use this to run my app.
Only problem is I can't run a script before running my app (as I do using launcher). That's why I'm studying a way of using LIPC to run that script when my app is launched!